1. Field of the Invention
The present invention relates to a preoperative planning program and an operation support jig for hip replacement arthroplasty using a data processing apparatus such as a personal computer.
2. Description of the Related Art
A knee joint or a hip joint constituting a part of human lower extremities is a particularly important joint for walking and others in daily life. Because of such a high requirement, such a joint is a region which is apt to suffer a traumatic injury, has a joint cartilage that is subjected to degenerative destruction with aging, and is often led to arthroplasty.
As a surgical treatment for this arthroplasty, total arthro-plasty for removing a destroyed cartilage, implanting metal in this part, and surgically creating a joint function by contact of this metal and plastic such as polyethylene is currently provided all over the world as the most stable method that can improve the function.
At this time, future durability of a prosthetic joint is greatly affected by respective installation positions of a femoral component and a tibial component in a knee prosthesis and a femoral stem and an acetabular cup in a hip prosthesis, i.e., precision of extraction of each bone (osteotomy).
In conventional technologies, as to installation of this joint prosthesis, a contour of the joint prosthesis printed on a transparent sheet is superimposed on an X-ray image acquired from a front side and a lateral side before a surgical operation to determine positions or sizes of the components, the stem, and the cup. However, according to such a method, grasping of a bone shape is affected by an imaging direction of the X-ray image or a patient's position at the time of imaging, and precision is insufficient.
To solve this problem, there has been considered a method using computer software that performs X-ray imaging in two directions at an oblique angle of 60° with respect to a frontal view in a standing position by using a special imaging platform which is positioned between a film and an irradiation point in a calibration frame in advance, aligns a three-dimensional model of a bone shape created from an X-ray CT device or an MRI device to each bone shade with respect to this acquired image (image matching), and three-dimensionally grasps a bone shape in the standing posture as a reference of an installation position.
According to this method using the computer software, sizes and positions of the joint prostheses matched to the bone shapes and a load environment can be determined by reading out three-dimensional shape models using computer-aided design (CAD) data of the joint prostheses (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2004-008707 (which will be referred to as “Patent Literature 1” hereinafter).
However, the technology described in Patent Literature 1 merely enables a surgeon to easily know a bone resection face on a tibial side in knee replacement arthroplasty, and it can not be applied to the femoral side having a different bone shape or function axis or any other joint, e.g., a hip joint, which is likewise important in the lower extremities, as it is.
Therefore, in regard to the hip replacement arthroplasty, there has been desired provision of a preoperative planning program and an operation support jig for hip replacement arthroplasty which enable appropriately reflecting individual differences of a patient to accurately determine a reaming procedure of a pelvic acetabulum before an operation and managing a surgical operation accurately reproducing preoperative determined contents during the operation.